Red Dead Redemption 2

General

You get a brush for your horse from the early story quest "Exit Pursued by a Bruised Ego" given by Hosea in camp. If you start getting warnings about your horse's health core decreasing because it's dirty, its not a HUGE deal, but that quest is how you get the option to brush your horse clean.

Hunting

You have to sell perfect/Legendary pelts to the Trapper NPC in order to buy special outfits. If you donate a pelt to your camp, the Trapper won't be able to make clothing with it.

The Trapper has a set location in a certain town, but be can also be found in random places on the world map. His icon is a bear paw.

If you lose a Legendary pelt by getting killed while carrying it, the pelt will be added to the Trapper's inventory automatically as if you had sold it to him. All you lose out on is the money you would've made from selling it to him.